Go ahead and run a full set of numbers including CYA. Tell him not to bother with the Nature2 thing. We don't think too highly of those things around here.

Since his pool is cloudy and he will likely have to be cleaning his cartridge frequently as it filter stuff out of the water, best to use the sock method to add CYA.

Forget the flock. Bleach, bleach, bleach and filtration. Oh, and *POP!! Lots of it!

* = Pool owner patience!